In the past, in making dentures such as crowns, bridges, and complete dentures, at first an impression of oral cavity is taken (impression taking) and next a work called as bite registration, that is, a work of recording the positional relationship between the maxillary teeth and the mandibular teeth by means of the wax rim. This work is called “Bite Taking (BT)” in health insurance terms. By recording the occlusal position of teeth via this bite registration, a working model can be mounted on an articulator in the conditions similar to the actual shape of oral cavity, and then, on the working model, inspection can be made or the prosthesis can be made and adjusted. An articulator is a device which can simulate the jaw movement and the various occlusal positions on a working model for treatment and research in dental care. As articulators, various forms of apparatuses are developed according to the purpose such that the specific occlusal position such as centric occlusion is reproduced or the jaw movement such as lateral movement and protrusive sliding movement is reproduced (Patent Document 1).
A process of making artificial teeth involves that at first a primary impression is taken using impression materials and a gypsum model obtained from the primary impression is used to make the “tray” for taking impression, which is called the individual tray and then used to take precise impressions. The tray is actually put into the mouth to take impressions by making various movements such as chewing, pursing the lips, and protruding the tongue. Then, an impression material with high reproduction performance is then poured into the tray to obtain the precise impression. Impressions thus obtained are used to fabricate a gypsum model, which is the base (working model) for the dental technician to make dentures with technical operations.
Most important thing in fabrication of artificial teeth (denture) is “occlusion”. While the vertical dimension (also called occlusal vertical dimension, rest position, and high-low dimensions) is generally considered to be important for occlusion, alignment of the maxillary teeth and the mandibular teeth is not so simple but many measurements such as determination of the positions of the dental midline, the anterior teeth, and the horizontal jaw in addition to the position of the maxilla and mandible have to be performed. Furthermore, the measurements are not useful until they are performed under the conditions in which the bite registration is achieved on the firmly secured base.
Patent Document 1 discloses an occlusion adjustment apparatus in making dentures and Patent Document 2 discloses a method of recording information about the mandible using the recording bases for fabrication of dentures.